This invention relates to a method of distributing liquid in a turf root zone of turf growing on a soil surface, the turf including a first layer of grass including leaves a second layer of thatch including dead leaves and stems and a third layer including the root zone.
The present inventor in U.S. Pat. No. 4,907,516 issued Mar. 13, 1990 discloses a device for pulsed injection into the ground of liquid fertilizer. The techniques disclosed in this patent have been developed into a machine which is particularly useful for injecting liquid into turf in golf courses and similar situations where a high quality turf condition is required. The machine can be used for injecting various liquids, mainly water based, including pesticides, fertilizers, soil amendments, biologicals, polymers and aeration liquids. The machine has the advantage of ensuring that the liquids are placed under the leaves and thatch of the turf and this has the following advantages.
a) Subsurface placement mitigates surface toxicity. PA1 b) Subsurface placement maximizes pesticide efficacy. PA1 c) Injection of aeration liquids relieves surface compaction and heat stress. PA1 d) Injection of aeration liquids improves green pliability immediately.
The main concern of the above patent was that of obtaining a maximum depth of penetration since the prior art up till that time had been unable to obtain the required penetration depth to obtain proper placement of pesticides, fertilizer and similar materials. The techniques shown in the patent provided an injection nozzle which had a single injection nozzle opening projecting vertically downwardly so as to generate a solid stream of the liquid which is injected vertically downwardly into the soil to obtain maximum depth. Maximum depth is further obtained by injecting the material from the nozzle opening in a series of pulses so that the pressure of the liquid can be maximized without the necessity for injecting large quantities of the liquid. The series of pulses therefore provide injection of the liquid into the soil at a series of locations spaced along a direction of movement of the machine.
The machine manufactured according to the patent provides a single row of the injection nozzles across the width of the machine which in one practical example are spaced at three inch spacing. The spacing of the individual pulses in the direction of movement can therefore be adjusted by changing the time and spacing between the pulses or by changing the forward velocity of the machine. In one particular example, the spacing between the pulses in the direction of movement can be either three inches or can be reduced to one and a half inches for increased application or more for decreased application.
It is known in spray nozzles for example those sold under the trademarks Fogjet and Twinjet manufactured by Spraying Systems Co of Wheaton Ill. to provide a plurality of nozzle tips on a single nozzle which direct spray outwardly from the nozzle in a plurality of different directions. Generally these nozzle tips are arranged to generate an atomized spray for maximizing a spray coverage. Certainly these nozzle tips are entirely unsuitable for injecting liquid into the ground since the nozzles do not and cannot provide a solid stream of the liquid which is necessary to penetrate the soil surface.
It is yet further known to provide nozzles for dribbling liquid onto a standing crop which include more than one nozzle opening. Thus for example nozzles manufactured by Spraying Systems define three jets or streams which are formed as a solid stream of the liquid. However the nozzle is mounted at a spacing well above the soil surface and the liquid to be dispensed is supplied at very low pressure so as to dribble or trickle liquid down from the raised position through the leaves of a standing crop onto the ground with minimum contact with the crop to minimize burning or damage to the crop from the toxicity of the liquid.
However none of these prior art arrangements are in any way concerned with the subject matter of the above patent and the present invention which provides the injection of liquids directly into the soil from a position closely adjacent the soil with high pressure liquid and none of the prior art provides any teaching nor disclosure concerning the placement of the liquid in the sub soil condition.